Infrared Thermowell Assembly for Accurate Process Temperature Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing temperature measurement methods using thermocouples or resistance-based detectors in thermowells suffer from errors due to infrared radiation interference from the thermowell walls, leading to inaccurate process temperature readings.
Innovation Solution
A thermowell assembly with an infrared sensor that incorporates a radiation shield and focusing mechanism to reduce infrared radiation from the thermowell walls while enhancing radiation reception from the distal end, using materials with low emissivity or polished surfaces and a beam guide to focus radiation onto the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared sensor is used to measure temperature in a thermowell, then temperature measurement capability is improved, but measurement accuracy deteriorates due to infrared radiation interference from thermowell walls
Solution Approach 1:
A radiation shield is introduced as an intermediary component between the infrared sensor and the thermowell walls. The shield selectively blocks infrared radiation from the walls while allowing radiation from the process fluid to reach the sensor, thereby eliminating the harmful interference without compromising the measurement capability
Solution Approach 2:
The radiation shield is positioned at a specific location within the thermowell bore, creating a localized modification to the radiation environment. By placing the shield only where it is needed (between the sensor and wall sources of interference), the solution improves measurement accuracy without affecting other aspects of the thermowell structure
2Measurement precision
If a radiation shield is added to reduce wall radiation interference, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The radiation shield is designed to perform multiple functions simultaneously: it blocks infrared radiation from the thermowell walls, maintains structural integrity of the thermowell assembly, and can be integrated with existing thermowell mounting structures. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves temperature measurement accuracy by minimizing wall radiation interference and enhancing signal fidelity from the process fluid, thereby reducing measurement errors.
Implementation Method 1
An infrared sensor detects infrared radiation from the distal end through the bore of the thermowell and responsively provides a sensor output related to the process temperature
Implementation Method 2
infrared radiation received by the sensor from a side wall of the bore is reduced. A radiation shield provided in the bore of the thermowell reduces infrared radiation received by the sensor from the side wall
Implementation Method 3
The radiation shield comprises an infrared beam guide positioned proximate the infrared sensor. The radiation shield is configured to operate as a focusing mechanism to focus radiation from the distal end of the thermowell onto the infrared sensor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A thermowell assembly for measuring a process temperature includes an elongate thermowell (20) having a proximal end (70) and a distal end (72). A bore (74) extends between the two ends with the thermowell assembly configured to extend into a process fluid. An infrared sensor (24) detects infrared radiation from the distal end (70) through the bore (74) of the thermowell (20) and responsively provides a sensor output (26). A configuration is provided in which infrared radiation received by the infrared sensor (24) from a wall of the bore (76) is reduced and/or radiation received from the distal end (70) of the bore is increased.